Pipe Diameter Calculator allows you to calculate the diameter of any pipe using this calculator. The calculator supports two units of measurements, SI Units and English/US Units. The calculator needs the following input to calculate the diameter: + Flow rate - This can be defined by selecting either Mass Flow or Volumetric Flow basis. + Density - Only required if using Mass Flow rate + Velocity in pipe. The application has a predefined list of services the includes typical velocities that can